Discourse-Based Reasoning for Controlled Natural Languages

Logic-based controlled natural languages usually provide some facility for compositional representation, minimally including sentence level coordination and sometimes subordination. Although these compositional forms suffice for representing short passages, they can become unwieldy for expressing entire paragraphs and documents. This paper describes an approach to representing larger composite texts in a controlled natural language. This approach, called discourse-based reasoning, integrates rhetorical structure theory with argumentation theory to define a model for defining composite structures and argument strategies in an ontological representation. Rhetorical structures are used to represent controlled texts, and argument strategies are defined for reasoning about interactions between structures. This provides the basis for expressing, summarizing, and interacting with explanatory and argumentative discourse. This would expand the scope of problems that may be addressed using controlled natural languages.